A. Field of the Invention
This invention relates to a switching mechanism in a circuit breaker.
B. Description of the Prior Art
A switching mechanism in a circuit breaker is known in the art in that a toggle link is provided between a latch locked by a trip mechanism and a holder bearing a movable contact. The toggle link is elastically urged by a switching spring which is elastically stressed when the circuit breaker is turned on or engaged to complete the circuit. When the circuit breaker is tripped, the latch is released from the trip mechanism and the elastic force of the switching spring moves the toggle link past a dead zone so that the movable contact is disengaged from the stationary contact by a snap action of known type. The dead zone refers to a state wherein the movable contact is stably engaged with the stationary contact. For example, Japanese Patent Application No. 98945/1982 discloses such a switching mechanism.
However, in the foregoing conventional switching mechanism, the disengagement of the movable contact from the stationary contact is effected only after the elastic force of the switching spring produces motion past the dead zone, thus resulting in an excessive tripping time. Therefore, in order to reduce the tripping time, it is essential to cause the elastic force to move the switching mechanism past the dead zone as quickly as possible once the tripping of the circuit breaker commences.